A) Field of the Invention
This invention relates to an electronic musical apparatus, more in detail, relates to an electronic musical instrument that can connect to the networks.
B) Description of the Related Art
There is an electronic musical instrument that can connect to a musical contents providing server on a communication network such as the Internet and download and purchase musical contents (for example, refer to Japanese Laid-Open Patent 2003-076364).
Normally, when musical contents are purchased on the communication network, it is necessary to input personal information such as a user ID, a password and the likes. It is known that the Cookie by which the personal information can be stored in the user's apparatus for omitting the inputting the personal information from the next time and which can be used for user identification.
The Cookie is a format wherein a Web site provider temporally stores data in a visitor's (the user) apparatus via the Web browser, and in which information relating to the user, time and date of visiting the site for the last time, the number of visiting times can be stored.
In transmission of the user ID and the password when purchasing the musical contents, security is necessary. The SSL protocol that transmits and receives encrypted information on the Internet is known as what prevents data tapping, data falsification and pretending by combining security techniques such as a public key encryption and a secret key encryption, a digital certificate (SSL certificate) and a hash function.
The above-described Cookie and SSL certificate have validation date, and it is necessary to always keep a current time on the apparatus side to use the Cookie and the SSL certificate. Generally, since the electronic musical apparatus such as an electronic musical instrument cannot keep the current time inside the apparatus as different from a personal computer, it is difficult to receive an internet service requiring a current time.
Moreover, an network time protocol (NTP) sever is used as a server to be connected for obtaining time information on the Internet; however, some types of the Internet connection prohibits NTP usage, and the time information cannot be obtained by the NTP.